The present invention relates to a sheet storing device that stores a large number of sheets, a post-processing apparatus equipped with the sheet storing device and an image forming system equipped therewith, and in particular, to a sheet storing device that stores folded sheets.
A folded sheet takes a condition that plural sheets are superposed by folding operations to bulk up by swelling and to tend to take an irregular shape.
Conventionally, in the post-processing apparatus connected to an image forming apparatus, sheets folded and ejected have been stored in a box-shaped storing device under the irregular condition.
Therefore, there have been problems including that a capacity of the storing device runs short, that the ejected sheets scatter and that the management of the stored sheets is troublesome.
In Patent Document 1, there is disclosed a sheet storing device that aligns folded sheets to store them.
In the sheet storing device disclosed by Patent Document 1, sheets fed into the sheet storing device continuously are stopped temporarily by a stopping roller to avoid a lift of the sheet, and then the sheet is conveyed to a sheet storing section.
Patent Document 1 discloses two types of sheet storing devices, and in the first one of them, a succeeding sheet is inserted to be under a preceding sheet, whereby, a sheet is inserted into the bottom of sheets in the sheet storing section, thus, the sheets are stacked vertically in the lying situation in the sheet storing section. In the second one of them, a succeeding sheet is supplied onto the upper side of a preceding sheet, and sheets are stacked to be inclined at the storing section.
It is desired that the sheet storing device that stores folded sheets is capable of storing sheets aligned well. The Patent Document 1 satisfies this condition to some extent but does not have enough yet.
According to the aforementioned first type of the Patent document 1, sheets are piled up to be stored and an irregular storing condition occurs easily without any means to maintain the stacking condition. Further they may collapse when the storing amount increases.
As the storing amount increases, the pressure on the bottom portion of the stored sheets is enhanced to make it difficult to insert a sheet into the bottom portion, which brings a limit of storing amount.
According to the aforementioned second type of the Patent document 1, the storing condition tends to be irregular easily and there is a problem that the management of the stored sheets is not easy.
[Patent Document 1] Unexamined Japanese Patent Application Publication No. 11-35211